Matches between which of the following are important because they represent references from one relation to
another and establish the connections among these relations?
A.
foreign key to primary key
B.
foreign key to candidate key
C.
candidate key to primary key
D.
primary key to secondary key
Explanation:
A foreign key is an attribute in one table that references or matches the primary key of another table. The
primary key is the attribute that is used to ensure that each row or tuple in a table unique. Together, the foreign
key and the primary key ensure referential integrity.
Incorrect Answers:
B: Candidate keys are a subset of attributes that from which the database developer can choose the primary
key to uniquely identify any tuple or record in a table. There are usually more than one candidate key attributes
in a table.
C: A foreign key is an attribute in one table that references or matches the primary key of another table.
Candidate keys are a subset of attributes that from which the database developer can choose the primary key
to uniquely identify any tuple or record in a table.
D: Secondary keys are candidate keys that have not been chosen as the primary key. The primary key is the
attribute that is used to make each row or tuple in a table unique. Candidate keys are a subset of attributes that
from which the database developer can choose the primary key.Harris, Shon, All In One CISSP Exam Guide, 6th Edition, McGraw-Hill, New York, 2013, pp. 1174, 1179-1180,
1181
Stewart, James, Ed Tittel and Mike Chapple, CISSP: Certified Information Systems security Professional Study
Guide, 5th Edition, Wiley Publishing, Indianapolis, 2011, pp. 276, 312
http://databases.about.com/cs/specificproducts/g/candidate.htm
http://rdbms.opengrass.net/2_Database Design/2.1_TermsOfReference/2.1.2_Keys.html